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Mate fidelity, senescence in breeding performance and reproductive trade-offs in the barn swallow

Authors

  • Nicola Saino,

    Corresponding author
    1. Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, I-20133 Milano, Italy; and
      Nicola Saino, Dipartimento di Biologia, via Celoria 26, I-20133 Milano, Italy. Tel: + 39 0258354808. Fax: + 39 0258354802. E-mail: n.saino@mailserver.unimi.it
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  • Roberto Ambrosini,

    1. Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, I-20133 Milano, Italy; and
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  • Roberta Martinelli,

    1. Dipartimento di Biologia, Università degli Studi di Milano, via Celoria 26, I-20133 Milano, Italy; and
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  • Anders Pape Møller

    1. Laboratoire d’Ecologie Evolutive Parasitaire, CNRS FRE 2365, Université Pierre et Marie Curie, 7 quai St. Bernard, Case 237, F-75252 Paris Cedex 05, France
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Nicola Saino, Dipartimento di Biologia, via Celoria 26, I-20133 Milano, Italy. Tel: + 39 0258354808. Fax: + 39 0258354802. E-mail: n.saino@mailserver.unimi.it

Summary

  • 1Senescence is defined as the decline in performance with age, and can be determined by diverse mechanisms such as accumulation of mutations, ‘wear and tear’ and antagonistic pleiotropy. Animals can mitigate the negative effects of senescence on reproductive performance by acquiring experience as they age.
  • 2We analysed the effect of age on clutch size, breeding date, fledging success and offspring quality (morphology and T cell-mediated immunity) of barn swallows (Hirundo rustica, Linnaeus) by comparing the progeny of individuals of known age during consecutive years.
  • 3Reproductive performance had no significant effect on probability of divorce, and adults that re-mated with each other had no reproductive advantage.
  • 4Body size, feather development and T cell-mediated immunity declined with paternal and/or maternal age already after the first breeding season. Body mass declined after paternal age of two years. T cell-mediated immunity of nestlings in one year covaried negatively with that of their siblings the previous year.
  • 5Hence, barn swallows suffer an age-dependent decline in offspring quality, and apparently trade quality of current offspring against that of subsequent reproductive events, although causality of this relationship could not be assessed in this correlational study.

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